Aircraft protective system



4 Nov. 27, 1945. H. E. BAER AIRCRAFT PROTECTIVE SYSTEM Filed May 15, 1941 TANK-2- F6 A I I FUEL TAN/f I I I I I I x INVENTOR H u/ard E. Baer BY I W 772 7 AT/ RNEY Patented Nov. 27, 1945- 2,389,754 I i aracam rnornc'rrvn srs'mm Howard E. Baer, Garfield, N. J., assignor Bendix Aviation Corporation, South Bend,'

Ind., a corporation of D elaware Application May 15, 19 "Serial No. 393,635

4 Claims. (omit-13s) This invention relates to aircraft, and particularly to the protection of aircraft against damage by fire or other hazard following rupture of a fuel line supplying one or more of the crafts engines and occasioned by engine displacement or loss.

It sometimes occurs, particularly in military combat, that the fuel line between the fuel source and the engine of an aircraft is ruptured by the displacement or loss of an engine. A rupture of this character permits spilling and waste of the fuel at the point or points of the rupture with the result that not only the available fuel supply is reduced for utilization by remaining engines not displaced but a fire hazard is thus created. The present invention removes both these sources of trouble by providing automatically acting means for sealing the broken fuel line, or lines, at or adjacent the fuel source and in response to engine displacement or loss.

Other features of the invention will become apparent from inspection of the following specification when read with reference to the accompanying drawing wherein is illustrated the preferred embodiment of the invention. It is to be expressly understood, however, that the drawing is for the purpose of illustration only, and is not designed as a definition of the limits of the inven tion, reference being had to the appended claims for this purpose.

In the drawing,

Fig. 1 is a diagram of the control system, shown in its relationship to a craft whose fuel supply is to be controlled;

Fig. 2 is a diagram of an alternative form of control; and

Fig. 3 is an internal view of certain parts of the automatic switch.

In the drawing reference character 5 designates the fuel tank, or one of a series of fuel tanks, carried by a plane 6 having a corresponding series of engines, of which one is shown at 1. Within the nacelle 8, which carries the engine 1, is a control valve ll, corresponding to that shown and claimed in application of Charles I. MacNeil, No. 392,522, filed May 8, 1941, and owned by the assignee of the present application. A similar control valve (not shown) is provided in the nacelle (not shown) on the other wing of the craft, and these units are adapted to be actuated initially by switches l3 and I 4, respectively, located in the cock-pit, or pilot's compartment; both switches being in circuit with source l8. If more than two engines are used, there will, of course, be additional control valves, with corresponding electrical connections.

thus stop fuel flow the former leading from pump 4| which delivers and 22, respectively; said solenoids being separately grounded, as shown at SI and 62. Switch I I5 is the automatic element, to be further described.

Closure of switch I3 (momentarily only) takes place at the outset. This momentary closure of switchl3 causes solenoid 2| to raise plunger 23, thus opening valve I I and causing spring 12 to press latch 24 into locking engagement with sear 2 1, as shown in Fig. 1. This relationship continues during normal flight f the craft, thus permitting free flow of fuel past the open valve H, and into the pump 4| of engine 1. Should there be some extraordinary occurrence, however, such as a displacement or loss of the engine 1, as by military casualty, the taut cable 60, which is connected to and between the engine 1 and the lever 96 of the switch II, will be slackened or severed with the result that the switch 15 is operated to close a circuit from the source 40 to energize the solenoid 22, thus withdrawing latch 24 and per, mitting spring 3| to reclose the valve ll. Loss of fuel is thus prevented when the pipe 36 is ruptured due to the displacement or loss of the engine. As an additional feature, an electric or electromagnetic valve control (Fig. 2) may be placed in circuit with switch 15, to permit'establishment of a flow; diverting path from tank 5 to a second tank 5A serving the surviving engine.

The automatic switch l5 may be of any suitable construction involving a spring-biasing of the contact element toward circuit-closing position; one form of biasing spring being indicated at 91 in Fig. 3. Whenever cable 63 is severed, this spring 91 snaps the lever 96 from the position shown in Fig. 1 (also Fig. 2) to the position shown in Fig. 3, in which latter position a circuit will be established for current flow from conductor 49 to conductor 52, and hence to solenoid 22, with the result heretofore described.

The complete switch spring. 91, bracket ments (not shown),

urged by a spr n Wires 5| and 52 lead from switches l3 and I5, respectively, to solenoids 2| 2 ment (not shown). The latter contact element is operably connected to a toggle 96 which is constantly urged into the position shown in Figure 3 by a spring 91 (see Figure 3). In this latter position to which it is thus biased, toggle 96 holds the switch contacts of the automatic switch I5 in engagement, one with the shifted in a clockwise direction about its pivot by force exerted through cable 60, thereupon the toggle 9B is shifted so as to open the contacts of switch l5. However, as above noted, any other suitable type of spring-biased switch may be substituted.

Cable 60 has one end secured to the engine (Fig. 1) and the other end to arm 96 of switch [5, and when taut it holds said arm in the switchopening position. When it slackens, due to breakage, the spring 91 snaps the switch to closed position, as above pointed out. i

What is claimed is:

1. In combination with a power plant having a fuel feed conduit connecting the fuel feed source to the engine of said plant; valve means connected in said conduit and effective for precluding the passage of fuel therethrough, at least a pair of coactable electrically actuated devices selectively operable for rendering said valve means efiective and inefiective respectively, a. switch in circuit with one of said devices for operating the latter to render said valve ineffective, a second switch in circuit with the other of said devices and effective for operating said other device to 2. In combination with a power plant having a fuel feed conduit connecting the fuel source to the engine of said plant; a valve connected other but when ing energization tive, solenoid means effective when deenergized upon defor maintaining said valve ineflective energization of said electromagnetic means, a

-switch in circuit with said solenoid means and efiective for causing energization of said solenoid means to render said valve effective, and a normal taut member connected between. said engine and said switch for rendering the latter ineffective when said member is taut.

3. The structure of claim 2 as set forth and' defined therein including, a second switch in circuit with said electro-magnetic means for rendering said latter means effective.

4. In combination with an aircraft having a separated pilot's compartment and a power plant having a fuel feed conduit connecting the fuel source to the engine of said plant; a valve con.- nected in said conduit and effective for precluding the passage of fuel therethrough, electromagnetic means connected to said valve and operable during energization for rendering said valve ineffective, solenoid means effective when deenergized for maintaining said valve inefiective upon deenergization of said electromagnetic means, a switch in circuit with said solenoid means and effective for causing energization of render said valve effective, and a normally tautsaid solenoid means to render said valve effective, a normal taut member connected between said engine and said switch for rendering the latter ineffective when said member is taut, and

$5 a second switch disposed in said compartment and connected in circuit with said electro-magnetic means for rendering said latter means effective.

HOWARD E. BAER. 

